Apparatus and method for measuring and adjusting golf club loft and lie

ABSTRACT

The invention provides an apparatus for measuring and adjusting golf club loft and lie that provides improved accuracy without unduly weakening the club. The apparatus includes clamping assembly configured to secure a golf club head in a stationary position and a shaft sensor system having two cameras spaced apart from the clamping assembly to provide a stereoscopic view of a shaft of the club, thereby facilitating real-time calculations loft and lie angles of the club. A clamping assembly configured to securely support a club head while bending forces are applied is also provided. The clamping assembly includes a face wall positioned to support a club face of the club head and a stationary side wall positioned to support the first longitudinal edge of a club head. The clamping assembly further includes two movable constraint blocks positioned in spaced relationship to the side wall to engage the second longitudinal edge of the club head. The blocks move independently relative to one another and are driven to engage the second longitudinal edge. The walls and the constraint blocks have compliant contact surfaces for engaging the club head without marring.

FIELD OF THE INVENTION

[0001] This invention relates generally to golf clubs and, more particularly, to apparatus and methods for measuring and adjusting a golf club's loft and lie.

BACKGROUND OF THE INVENTION

[0002] Loft and lie angles are important characteristics of a golf club. Unintended variations in loft and lie can have a pronounced effect on a golf club's performance. As such, the manufacture of golf clubs often includes steps of measuring and, if necessary, adjusting loft and lie. Also, golf clubs can be customized to a particular golfer by adjusting loft and lie.

[0003] Adjustments are commonly performed using an iterative approach. First, loft and lie are measured using a particular device for that purpose, e.g., an angle inspection device. Typically, a technician clamps the club to the device in a prescribed orientation and reads the angle measurements off protractor-like analog scales. Such devices typically have an accuracy of only ±0.5 degrees when used by a skilled technician. Those of less skill may have difficulty properly aligning the club in the device and properly reading the analog scales, resulting in measurements that are even less accurate. If adjustments are required, the technician secures the club to a clamping device and applies force to bend the hosel, thereby adjusting loft and lie to the desired degree. However, the direction and amount of force applied is at the technician's estimation. Thereafter, the technician returns the club to the measuring apparatus to assess whether additional bending will be necessary. This process is repeated until the desired loft and lie are achieved.

[0004] Current approaches are highly dependent upon the skill of the technician, and even the most skilled typically cannot achieve accuracy better than ±0.5 degrees. Even a skilled technician often requires several attempts to achieve the desired angles. However, multiple bending attempts can weaken the club head, particularly the hosel, and increase the risk of breakage.

[0005] It should, therefore, be appreciated there is a need for an apparatus for measuring and adjusting golf clubs that allows a technician to achieve improved accuracy m measuring and adjusting a golf club's loft and lie without unduly weakening the club. The present invention fulfills this need as well as others.

SUMMARY OF THE INVENTION

[0006] The present invention provides an apparatus, and a related method, for measuring and adjusting golf club loft and lie that provides improved accuracy without unduly weakening the club. The apparatus includes a clamping assembly configured to secure a golf club head in a stationary position and a shaft sensor system having two cameras spaced apart from the clamping assembly to provide a stereoscopic view of a shaft of the club. The apparatus further includes a computing device programmed to use information received from the shaft sensor system to provide real-time calculations of loft and lie angles of the club. In use, a technician can measure and adjust loft and lie without transferring the club from one device to another. Also, the progress toward achieving the desired loft and lie can be monitored while doing an adjustment. Moreover, the apparatus is relatively easy to use, thereby allowing even less skilled technicians to adjust loft and lie within tight tolerances.

[0007] In a preferred embodiment, the apparatus further includes a positional system in communication with the computing device. The positional system includes first sensor, e.g., a clamp inclinometer, mounted to the clamping assembly and a second sensor, e.g., a structure inclinometer, mounted to the supporting structure. The sensors are preferably configured to sense orientation in two axes relative to gravity. In this manner, the relative orientation of a club head in the clamping assembly and the shaft sensor system can be provided.

[0008] In a detailed aspect of a preferred embodiment, the apparatus includes a clamp mount joining the clamping assembly to a supporting structure. The clamp mount has an x-axis trunnion and a y-axis trunnion to provide two degrees of freedom for the clamping assembly.

[0009] In another detailed aspect of a preferred embodiment, the apparatus includes a face sensor system disposed about the clamping assembly to monitor the orientation of the club face and, preferably, the face sensor system has a camera positioned to view a club face within the clamping assembly.

[0010] In an independent aspect of the present invention, a clamping assembly configured to securely support a club head while bending forces are applied is provided. The clamping assembly includes a face wall positioned to support a club face of the club head and a stationary side wall positioned to support the first longitudinal edge of a club head. The clamping assembly further includes two movable constraint blocks positioned in spaced relationship to the side wall to engage the second longitudinal edge of the club head. The blocks move independently relative to one another and are driven to engage the second longitudinal edge. The walls and the constraint blocks have compliant contact surfaces for engaging the club head without marring.

[0011] In a detailed aspect of a preferred embodiment, the contact surfaces of the side wall and the movable constraint blocks are angled toward the face wall, thereby encouraging the club face to mate flush with the face wall as the constraint blocks engage the second longitudinal edge of the club head.

[0012] In another detailed aspect of a preferred embodiment, the clamping assembly further including a second stationary side wall positioned on an opposite side of the constraint blocks relative to the first side wall; wherein the face wall extends between the first and second side walls.

[0013] In another independent aspect of the invention, the shaft sensor system and the computing system are configured locate the shaft within a three-dimensional coordinate system and, preferably, a center line of the shaft is computed based upon the resulting stereoscopic view. In preferred embodiment, a linear array of lighting devices is orthogonally aligned relative to the mounting plane of the shaft sensor system to illuminate the shaft.

[0014] Other features and advantages of the present invention should become apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings in which:

[0016]FIG. 1 is a front perspective view of an apparatus for measuring and adjusting golf club loft and lie in accordance with the invention.

[0017]FIG. 2 is a perspective view of a golf club, depicting a lie and shaft lines and a face plane.

[0018]FIG. 3 is a cross-sectional view taken along line A-A of the golf club of FIG. 2, depicting a loft angle.

[0019]FIG. 4 is a close-up, perspective view of the clamping assembly of the apparatus of FIG. 1, depicting moveable constraint blocks.

[0020]FIG. 5 is a perspective view of the clamping assembly of the apparatus of FIG. 4, with a top plate removed.

[0021]FIG. 6 is a partially exploded view of the face sensor system of the apparatus of FIG. 1, depicting the face sensor system and relative positioning to a face pad of the clamping assembly.

[0022]FIG. 7 is a simplified block diagram of sensor systems, computer and control system of the apparatus of FIG. 1.

[0023]FIG. 8 is a simplified display screen generated by a computing device of the apparatus of FIG. 1, depicting a bull's-eye chart having concentric rings centered on a bull's-eye for monitoring progress toward a desired loft and lie.

[0024]FIG. 9A is simplified perspective view of the shaft sensor system of the apparatus of FIG. 1, depicting a projected view area of a z-axis camera.

[0025]FIG. 9B is simplified overhead view of the z-axis camera and the light source of the shaft sensor system of the apparatus of FIG. 1, depicting a projected view area of the z-axis camera.

[0026]FIG. 9C is simplified overhead view of the z-axis camera and the light source of the shaft sensor system of the apparatus of FIG. 1, depicting a bisecting line passing through the shaft center and reflection point.

[0027]FIG. 9D is simplified overhead view of the shaft sensor system of the apparatus of FIG. 1, depicting a predicted reflection point as viewed from an x-axis camera.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028] With reference to the illustrative drawings, and particularly FIG. 1, there is shown an apparatus 10 for measuring and adjusting the loft and lie of a golf club 12. The apparatus includes a clamping assembly 14 that securely receives the head of the golf club and a plurality of sensor systems configured to provide real-time monitoring. A face sensor system 16 is disposed about the clamping assembly to monitor the orientation of the club face 18. A shaft sensor system 20 is spaced apart from the clamping assembly to monitor orientation of the club's shaft 22, and a positional sensor system 24 is disposed about the apparatus to provide positional relationship of a club face and the shaft sensor system. The apparatus includes a computer 26 that receives data from the sensor systems from which it calculates loft and lie. Loft and lie angles (Lo_(o) L_(i), respectively) are measured from an axial line of the shaft, i.e., shaft line 28, to a face plane 30 and a lie line 32, respectively (FIGS. 2 and 3). Loft and lie information is graphically displayed in real-time on a touch screen monitor 34, to depict progress toward a desired loft and lie while an adjustment is underway. Thus, the apparatus is relatively easy to use, allowing minimally skilled technicians to adjust loft and lie within tight tolerances.

[0029] The shaft sensor system 20 includes two cameras sensitive to infrared light, i.e., an x-axis camera 36 and a z-axis camera 38, spaced apart from each other to provide a stereoscopic view of the shaft 22. Alternatively, any imaging system that can be configured to provide a stereoscopic view can be used, including video cameras, photocell devices, and laser scanners. Given the stereoscopic view of the shaft, the shaft line 28 can be defined three-dimensionally relative to the IR cameras, without need to maintain the shaft stationary. If the orientation of the two IR cameras is known relative to the club face, loft and lie can be determined. In this embodiment, the positional system 22 serves to monitor the relative orientation of the face plane and IR cameras, and the face sensor system 16 monitors the orientation of the lie line 32 along the face plane 30. In other embodiments, the relative orientation of the clamping assembly 14 and shaft sensor system can be structurally fixed or measured prior to use.

[0030] With continued reference to FIG. 1, the clamping assembly 14 is rotatably mounted for two degrees of freedom to a clamp mount 40 having an x-axis trunnion 42, and a y-axis trunnion 44. Handles 46 are provided for rotating the clamping assembly and actuators 48 are disposed thereon that release brakes 50, 52 attached to each trunnion. In use, the technician rotates the clamping assembly so the club shaft 22 is generally vertical, thereby centering the shaft in stereoscopic view of the shaft sensor system 20. Once in the desired orientation, the user releases the actuators, activating the brakes to lock the clamping assembly in place.

[0031] With reference now to FIGS. 4 and 5, the clamping assembly 14 defines two club-head pockets 54, 56, one for right-handed clubs and another left-handed clubs. The clamping assembly includes a rigid face wall 58 for engaging the club face 18 and stationary side walls 60 each for supporting a sole 62 (FIG. 3) of the club head. A top edge 64 (FIG. 3) of the club head is supported by movable constraint blocks 66 of the clamping assembly. Top-edge mar pads 68 are pivotally mounted to the constraint blocks for both right-handed and left-handed clubs. The clamping assembly further includes a face mar pad 70 attached to the face wall and sole mar pads 72 pivotally attached to the side wall. The mar pads provide a compliant contact surface for the club head. The club head is inserted such that the sole abuts the sole mar pads and the club face is generally flush against a face mar pad. The clamping assembly is configured to withstand relatively significant bending force applied to the club while maintaining the club head secure.

[0032] The clamping assembly 14 further includes motors having stall sensors (not shown) operable by a foot pedal 74 (FIG. 1) to drive the constraint blocks 66. The blocks slide independently of one another until the top-edge mar pads 68 securely abut the top edge 64 of the club head, at which point motors will stop. The constraint blocks securely maintain their position even in the face of relatively significant bending force applied to the club. Preferably, the mar pads of the side wall and the movable constraint blocks are angled toward the face wall. Thus, as the constraint blocks engage the top edge of the club head, the club face is encouraged to mate flush with the face wall.

[0033] With reference now to FIGS. 1 and 6, the face sensor system 16 includes two IR-sensitive cameras, i.e., left and right face cameras 76, 78, respectively, each positioned over an opening 80, 82 in the face wall 58 such that the corresponding camera can view a club face abutted thereto and includes a lighting device 86 to illuminate the club face 18. The lighting device includes a two rows of red LEDs (not shown) mounted to a board, such that there is one row for each club pocket 54, 56. The light from the LEDs is routed to the club face via a light pipe 87, and the reflection of the light off the club face is received by the corresponding camera. The IR camera and the lighting device are oriented such that the grooves of the club face show prominently. Each face camera is mounted such that the resulting images are orthogonally aligned with the clamping assembly. Thus, angle of the grooves in the resulting image relates to the lie line 32 orientation in the face plane 30 (FIG. 2).

[0034] With reference again to FIG. 1, shaft cameras 36, 38 are mounted to a lateral support 88 positioned above the clamping assembly 14. The shaft cameras are spaced apart and directionally oriented at a 90-degree angle relative to one another such that the stereoscopic view is centered on the vertically oriented shaft 22 extending from the clamping assembly. The shaft sensor system further includes a shaft IR lighting device 90 generally centered between the shaft cameras for illuminating the shaft. In this embodiment, the lighting device is a linear array of IR lighting devices orthogonally aligned relative to the mounting plane of the shaft cameras. This configuration provides sufficient light along the shaft's length and throughout its range of motion.

[0035] With reference again to FIGS. 1 and 6, the positional system 24 includes a clamp inclinometer 92 mounted to sense the orientation of the clamping assembly and a structure inclinometer 94 mounted to sense the orientation for the structure. In this embodiment, the structure inclinometer is mounted to the lateral support 88 to which the shaft cameras are mounted. The inclinometers measure orientation in two axes relative to gravity and both inclinometers are aligned with the x and y axes of the clamping assembly. The clamp inclinometer is mounted to be generally planar with a club face secured by the clamping assembly 14, thereby allowing the orientation of the shaft cameras 36, 38 relative to the club face to be known. Since the inclinometers provide relative alignment to one another, it is not necessary for the apparatus to be precisely level. In other embodiments, any sensor system that can be configured to provide positional relationship of the club face and the shaft sensor system can be used, including those implementing gyroscopes, levels and other positional sensors, either singly or in combination. Alternatively, this positional relationship can be fixed.

[0036] With reference now to FIG. 7, the sensor systems 16, 18 and 22 are controllable from the computer 26. The computer includes input cards, frame grabbers 96 such as Imagenation® PXR 800, for receiving video input from the IR cameras 36, 38, 76, and 78 and an A/D card 98 for receiving input from the inclinometers 92, 94. A programmable logic controller, PLC 100, is connected to a serial port 102. The PLC receives input from the foot pedal 74 and air pressure actuators 48, the x- and y-axis trunnion brakes 50, 52 and serves to control operation of the clamping assembly 14. The PLC also provides data to the computer regarding the state of the clamping assembly for display to the technician, which is displayed upon the monitor.

[0037] The computer 26 computes shaft angle measurements at a rate of 12 per second, correlating to capturing at least 12 frames per second from each shaft camera 36, 38. Since the club head is generally static within the clamping assembly 14, it is monitored primarily for slippage. The control system computes lie line measurements at a rate of 2 per second, correlating to a frame captures of at least 2 frames per second. Once the clamping assembly is oriented, the inclinometers 92, 94 are also generally static. Measurements of the inclinometers are updated twice per second. Differences in measurement are often attributable to chassis deflection during high force bending.

[0038] With reference now to FIG. 8, a bending screen 104 provides a convenient graphic display to aid the technician in bending the club. The bending screen displays the status of the clamping assembly 14 in text boxes 106, indicating overall status and whether the clamp and trunnions are locked. Using either the touch screen 34 or a keyboard 108 (FIGS. 1, 7) the technician can input the desired loft and lie. Optionally, the computer 26 can be connected to a network 109, e.g., the Internet, to receive desired angles directly from retailers or consumers. The bending screen includes a bull's eye chart 110 having concentric rings 112 centered about a graphical center, i.e., a bull's-eye 114, representing the desired loft and lie. To input the desired loft and lie, the technician can first select, or input, the type of club using boxes 120 and input the desired offset of loft and lie using boxes 116, 118, respectively. The chart is a two-dimensional plane in which loft is defined along an x-axis and lie is defined along a y-axis. In this embodiment, the axes are not displayed. The club's real-time loft and lie and the desired loft and lie are numerically displayed in text boxes 122 and 124. A circular shaft icon 126 graphically represents the real-time loft and lie relative the bulls-eye. Even relatively subtle movement of the shaft will cause movement of the shaft icon in the bull's-eye chart. The technician can, therefore, test the bending direction prior to applying bending force and can monitor amount and duration of bending force until the desired loft and lie are achieved, as represented by guiding the shaft icon into the bulls-eye center.

[0039]FIGS. 9A-9D depict a preferred approach for determining the shaft line's orientation in the shaft-sensor coordinate system. Generally, the module uses the captured image from the z-axis camera 38 to approximate the positioning of the shaft line in a shaft sensor coordinate system. Based upon the approximation, it calculates how the shaft would appear to the x-axis camera 36 and compares that to the actual image. Differences between the calculated and actual images are used to iteratively refine the predicted location of the shaft. Preferably, the computer is programmed to account for lens distortion attributable to the cameras.

[0040] The shaft-sensor coordinate system is defined as a right-handed coordinate system having an x-axis extending from the origin 130 outwardly along the view line of the x-axis camera 36. The z-axis extends from the origin outwardly along the view line of z-axis camera 38, and the y-axis is orthogonal to the x-z plane. Since the camera positions and view angles are known, a field of view of a known size, i.e., a projection area 128, for the z-axis camera can be defined in the x-y plane. The size of the projection area can be defined in both pixels and centimeters, thereby allowing conversion from the captured image to the shaft-sensor coordinate system.

[0041] As previously discussed, the images from the shaft cameras 36, 38 are captured by frame grabbers 96. The captured images are processed to define points of reflected light. The processed points from the z-axis camera are converted to the shaft coordinate system by projecting the point on to the projection area 128. A projection line (L_(p)) is then defined extending from the z-axis camera to the projection point. The actual location of the shaft point is along this line. As depicted in FIG. 9C, given that the relative positions of the camera and shaft IR lighting device 90 are known, a shaft center point (C) can be determined by bisecting an angle (A) originated at the point of reflected light. The center point is a distance from the reflection point along the bisecting plane equal to the shaft radius (r). A database having radius profiles for various types of club shafts may be provided.

[0042] As depicted in FIG. 9D, a reflection point (P_(e)) as viewed by the x-axis camera 36 can be predicted given the estimated center point (C) and the positions of the IR lighting device 90 and x-axis camera 36. A ray (R_(l)) extending from the light to the estimated center point is defined, and a ray (R_(x)) extending from the x-axis camera to the estimated center point is also defined. A line segment (L_(s)) extending between intersection points of the rays is defined. A radius (r) bisects the line segment and defines the predicted reflection point (P_(e)). The predicted reflection point is compared to the actual refection point observed by the x-axis camera. If it is to the right of the observed reflection then the estimated center point is refined to be closer to the z-axis camera along the projection line (L_(p)). If it is to the left, then the estimated center point is refined to be farther from the z-axis camera.

[0043] It should be appreciated from the foregoing that the present invention provides an apparatus and a related method for measuring and adjusting a golf club's loft and lie with improved accuracy and without unduly weakening the club. The apparatus includes a clamping assembly configured to secure a golf club head in a stationary position and a shaft sensor system spaced apart from the clamping assembly to provide a stereoscopic view of a shaft of the club. The apparatus further includes a computing device programmed to use information received from the shaft sensor system to provide real-time calculations of loft and lie angles of the club. In use, a technician can measure and adjust loft and lie without transferring the club from one device to another. Also, the progress toward achieving the desired loft and lie can be monitored while performing an adjustment. Moreover, the apparatus is relatively easy to use, thereby allowing even less skilled technicians to adjust loft and lie within tight tolerances.

[0044] The foregoing detailed description of the present invention is provided for the purposes of illustration and is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Accordingly, the scope of the present invention is defined only by the claims set forth below. 

1. An apparatus for measuring loft and lie angles of a golf club comprising: a clamping assembly configured to secure a head of a golf club in a stationary position; a first camera and a second camera configured to provide a stereoscopic view of a shaft of a golf club secured by the claming assembly, wherein a first camera orientation and a second camera orientation are known relative to the face of the a club head secured by the clamping assembly; and a computing device programmed to use information received from the first and second cameras to calculate loft and lie angles of a golf club secured by the camping assembly.
 2. An apparatus as defined in claim 1, further comprising: a supporting structure coupled to the clamping assembly; a first sensor mounted to the clamping assembly and configured to sense orientation in two axes relative to gravity level; and a second sensor mounted to the supporting structure and configured to sense orientation in two axes relative to gravity level; wherein the first and second sensors are in communication with the computing device.
 3. An apparatus as defined in claim 1, further comprising a clamp mount joining the clamping assembly to the supporting structure, the clamp mount having an x-axis trunnion and a y-axis trunnion to provide two degrees of freedom for the clamping assembly.
 4. An apparatus as defined in claim 1, further comprising a light source for illuminating a shaft of a golf club secured by the clamping assembly.
 5. An apparatus as defined in claim 4, wherein the first and second shaft cameras are fixed relative to a supporting structure and directionally oriented at a 90-degree angle relative to one another such that a resulting stereoscopic view is centered generally above the clamping assembly.
 6. (canceled).
 7. An apparatus as defined in claim 1, further comprising a face camera positioned to view a face of a club secured by the clamping assembly.
 8. An apparatus as defined in claim 1, wherein the clamping assembly comprises: a face wall positioned to support a face of a club head and having a compliant contact surface for engaging the face; a side wall positioned to support a sole of a club head and having a compliant contact surface for engaging the sole; and at least one movable constraint block positioned in spaced relationship to the side wall to engage a top edge of the club head and having a compliant contact surface for engaging the top edge.
 9. An apparatus as defined in claim 8, wherein the contact surfaces of the side wall and the movable constraint block is angled toward the face wall to encourage the face to mate flush with the face wall when the constraint block engages the second longitudinal edge of the club head.
 10. An apparatus for adjusting loft and lie angles of a golf club comprising: a face wall positioned to support the face of a club head and having a compliant contact surface for engaging the face; a side wall positioned to support a sole of a club head and having a compliant contact surface for engaging the sole; a plurality of movable constraint blocks positioned in spaced relationship to the side wall to engage a top edge of a club head, each constraint block having a compliant contact surface for engaging the top edge, wherein the constraint blocks are configured to move independently relative to one another; at least one motor configured to move the constraint blocks to engage the top edge; and a controller in communication with the motor to control the movement of the constraint blocks.
 11. An apparatus as defined in claim 10, wherein the contact surfaces of the side wall and the movable constraint blocks are angled toward the face wall to encourage the face of the club head to mate flush with the face wall as when the constraint blocks engage the top edge of the club head.
 12. (canceled).
 13. An apparatus as defined in claim 10, wherein the compliant contact surfaces of the constraint blocks are pivotally mounted thereto. 14-15. (canceled).
 16. A method of measuring loft and lie angles of a golf club having a head and a shaft, the head having a face, the method comprising: securing the head in a clamping assembly; stereoscopically viewing the shaft with a first camera and a second camera, wherein the orientation of the first and second cameras is known relative to the face; directing stereoscopic information of the shaft from the fist and second cameras to a computing device; and calculating loft and lie angles of the golf club using the computing device.
 17. A method as defined in claim 16, wherein further comprising information from a positional system in communication with the computing device contributes to providing the relative orientation of the shaft sensor system and the face of the club head, the positional system including; measuring the orientation of the clamping assembly in two axes relative to gravity; measuring the orientation of a supporting structure fixed relative to the fiat and second cameras in two axes relative to gravity; and determining the orientation of the first and second shaft cameras relative to the face. 18-23. (canceled).
 24. An apparatus as defined in claim 1, further comprising a display in communication with the computing device for displaying the loft and lie angles of the golf club.
 25. An apparatus as defined in claim 4, wherein the light source is a linear array of infrared lighting devices aligned orthogonally relative to a mounting plane of the first and second shaft cameras.
 26. A method as defined in claim 16, further comprising displaying the loft and lie angle of the golf club on a display in communication with the computing device.
 27. A method as defined in claim 16, further comprising: viewing the club face with a face camera; and directing information from the face camera to the computing device.
 28. A method as defined in claim 16, wherein calculating loft and lie angles of the golf club using the computing device comprises: capturing a first image of the shaft from the first camera; determining an approximate shaft position in a shaft sensor coordinate system using the first image; capturing a second image of the shaft from the second camera; comparing the approximate shaft position with the second image; and determining the orientation of the shaft relative to the first and second cameras based upon the comparison. 